On 10/03/2011 04:12 PM, Lloyd E. Sponenburgh wrote:
fired this volley in
:

Can this happen with 240v 3 phase?

My building has only 240v. 800 amps service.


240 VAC (in any phase configuration) is less dangerous than, say 440.

But with 800amps of ability to deliver current, you have a great
potential for plasma-like arcs.

Typical 240 V breakers have a 10,000 Amp disconnect rating, and enough
internal inductance to limit fault current below that.

Typical 480 V breakers are vastly bigger, and have a 100,000 Amp rating.
The arcs there are more severe, due both to the voltage and limiting
current.

While 240 is nothing to ignore, the kinds of explosive arcs and arc
flash injury are really rare on 240.

Jon